Control of fuel feeding devices



WM 5AM CONTROL OF FUEL FEEDING DEVICES Filed Jan. 2, 1943,

INTERVAL 30 so I I5 ENVENTO R .Allmzrfi: E-BQQJL.

l ATTORNEY Patented Dec. 5, 1944 CONTROL OF FUEL FEEDING DEVICES Albert E. Baak, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application January 2, i941, Serial No. 372,784

19 Claims.

This invention is concerned with the control of fuel feeding devices, principally stokers, and is particularly directed to improvements in automatic systems for controlling stokers in respouse to temperature and time and to improvements in timing apparatus adapted for use in such systems.

It is common practice to control stokers' by means of a space thermostat and a timing device, the latter serving to intermittently operate the stoker .for fire maintaining purposes during mild weather. The control arrangement is' usually electrical, comprising circuits controlled by contact mechanism operated by the timing device and by the space thermostat.

The object of my invention is to provide an improved electrical system for controlling a stoker by a thermostat and a timer, the improvements residing in part in arrangements whereby control from the timer and adjustments of the timed operation are simplified so as to reduce the cost of manufacture and enable operators to adjust'the control with greater facility.

Another object is to provide a timingdevice embodying a fixed cam and a rotatable cam follower carried by the ratchet wheel of a pawl and ratchet mechanism operated by an electric motor, the mechanism being so constructed as to cause the ratchet wheel'to mov'e, the cam follower at a proper speed to produce the desired timing.

Another object is to provide a timing device embodying a cam having alternate dwells and depressions with improved adjustable means for blanking out one or more depressions to vary the relative number of dwells and depressions.-

Another object is to provide a timing unit embodying a relatively. fixed cam and a rotatable cam follower carried on a wheel adapted to be reciprocated in the direction of its axis.

Another object is to provide a timing unit embodying relative fiat cam members with a cam follower carried on a rotatable element located relatively close to the cam members and lying in the same plane so that the parts occupy a minimum of space.

Another object is to provide an adjustable cam having gaps in its periphery forming depressions between adjacent dwells with manually adjustable elements movable into positions for blanking out certainof the gaps to vary the relative number of dwells and depressions."

Numerous other objects and advantages of my invention will become apparent from the following detailed description wherein:

Figure 1 is a diagrammatic view of a stoker system embodying my invention.

Figure 2 is an exploded isometric view of certain detail parts of the timing mechanism.

Figure 3 is a plan view of the panel carrying the timing mechanism.

Referring to Figure 1 of the drawing, numeral l0 designates an automatic stoker of any well known type which forms part of a heating system not shown which may be any of various well known types of systems. My invention is primarily concerned with the mechanism for controlling the stoker which mechanism includes a space thermostat H which is of a known type. The thermostat ll comprises a circular bimetal element l2 having one end fixed and carrying two flexible switch blades is and M at its other end. The blades I3 and I4 cooperate with fixed electrical contacts l5 and I 6 respectively. The

thermostat H is so arranged that upon a fall in temperature the blades l3 and H are moved to the left, and at a predetermined temperature which may be 72? for example, blade l3 engages the contact l5. Blade l4 engages contact 16 at a predetermined lower temperature which may be one or two degrees lower for example, such that this temperature may be.70. The operation of this thermostat will be referred to again more particularly hereinafter.

The thermostat controls a relay 20 comprising a winding 2| having an armature attached to switch blades 22 and 23, the blades 22 and .23 cooperating with fixed electricalcontacts 24 and 25 respectively. When the winding 2| is energized, the armature is attracted so as to move the switch blades into engagement with their respective contacts. Power for operation of the relay is supplied by a stepdown transformer 21 comprising a primary winding 28 and a secondary winding 29, the primary winding having a greater number of turns than the secondary winding. Numerals 30 and 3| designate line conductors connected to a suitable source of power not shown. Numeral 32 designates a manual switch comprising a switch arm 33 which is normally in engagement with'a fixed electrical contact 34, Connected in series with the manual switch 32, as shown, is a fuse 35. The primary .asseenonl'igurol.

mechanism which forms the principal substance of my invention and which is generally designated by the numeral 40. The timing mechanism includes an electric timing motor which may be a well known Telechron motor and which is designated by the numeral I. The motor II includes an armature 42 mounted on a shaft 48 and a winding 44. The winding is connected across the line conductors II and Ii by a circuit extending from line conductor ll through a wire ll, winding 44 and wire it to line conductor Ii. Numeral l1 designates a casing which encloses a gear reduction train which forms a part of the Telechron motor, and extending from the casing 41 is a shaft 48 which is driven through the gear reduction train at a speed of one revolution per minute. On the end of shaft ll is acam ll having a graduall rising contour with a single dropofl'. The earn it has a cam follower ll riding thereon, and the cam follower is carried on the left end of a lever i pivoted on a fixed member HA. Pivoted to the rightend of lever II is a small lever l2 forming a pawl cooperating with a ratchet wheel 58. Referring to Figure 2, numeral ll designates a small coil spring attached to the lower end of pawl l2 and normallv urging the pawl in a clockwise direction against the teeth of the ratchet wheel It. The ratchet wheel II is mounted on a shaft ll which is iournaled in a panel II and on the end oi which is carried a manual rotating knob 51.

The cam follower II is below the cam ll as seen on Figure 1. As the cam It is rotated, the cam follower I is gradually moved downwardly.

as seen on Figure 1, that is to rotate the lever 2."

ll in a counter-clockwise direction, looking at Figure 2, so as to move the pawl I! upwardly and thereby mtate the ratchet wheel II in a clockwise direction as seen on Figure 2. when the cam follower ll drops of! the single dropoi'i on cam ll, the coil spring I acting on the pawl I! rotates the lever II in a clockwise direction keeping the cam follower II in engagement with the cam ll and bringing the pawl I! into engagement with the next lower tooth on the ratchet wheelll. As the cam it rotates, the ratchet wheel II is thus moved in a clockwise direction one tooth at a time. The ratchet wheel It has 'GOteethsothatitisrOtatedataspeedofone revolution per hour; pawl I2 being actuated once aminute.

The ratchet wheel II lies in a-plane parallel to that of panel II, and between the ratchet wheel and the panel II are a number of circular members, the structure of which may best be seen in Figure 2, wherein these members are shown spaced apart and isometrically. A plan ,viewofthepanelalisshowninl 'igureii.

The ratchet ,wheel II also has a hub is extending downwardly, as seen in Figure 1. The hub ll carries an insulating member II at its end which bears against a screw 82 carried at the midpoint of a contact bracket 0 made of spring material. The bracket is is fixed at its left end and at its right end it carries electricalcontacts N and IL The contact I cooperates with contact it carried on a contact bracket 81, and the contact ll cooperates with a contact ll carried on a contact bracket It. The bracket It is arranged so as to normally tend to spring upwardlysoastocausethescrew lltourge the huh I and the ratchet wheel It upward y the relay deenergised as in Figure l, the 'parts areintheposi onsshowninthatflgure 'member II, and this member is held against the panel II by brackets Ii and II. The engagement of the brackets I4 and II with the edge of member II is free enough to permit the member 11 to be rotated while it remains in the same relative positionas respects the shaft II; that is, it remains in a position with the shaft centrally disposed as respects the member 13. The member 13 has a pin 18 extending perpendicularly to the plane of its surface and through an arcuate slot 11 in the panel it (see Figures 2 and 3). Adjacent the slot 11 are graduations bearing numerals from 1 to 7, the purpose of which will be referred to more particularly hereinafter. Around the inner edge of the member 11 are arcuate openings or gaps II, II, It and II which are equally spaced angularly. As will presently appear, the portions of member 1! between the gaps form cam dwells with the gaps forming depressions between the dwells.

Numeral l4 designates a circular member having the same diameter as the inner diameter of the ring member II. The member ll has a central aperture ll through which the shaft ll passes, the member N not being fastened to the shaft but being non-rotatably fastened to panel II. The member I is disposed within the rin member 13, these members having the same thickness and lying in the same plane and both being flush with the surface of one side of panel I when the parts are in assembled relationship. The member 84 has three cut-outportions 88, ll and 90 which form gaps in its periphery. These cut-out portions are equally spaced angularly, being 90 apart, and they all have the same shape as best seen in Figure 2. Each of these openings has straight sides near the periphery of member II, and the sides then taper inwardly toward the center of the member 84.

the tapering portions connecting with rectilinear' Portions which form guide-ways as will presently be described. The guide-ways are desi nated by the numerals ll, I2 and II respectively. The member has another cut-out portion ll forming a gap in its periphery, this cut-out portion being spaced 90 from the cut-out portions II and II but having a different shape. The lower part of the cut-out portion 04 has the shape of an arcuate slot 05 as seen on Figure 2. Normally the gaps in the periphery of member ll lie adjacent the gaps in the ring member 13, and the amount of overlap of adjacent gaps may be varied by rotating the ring member 13. This may be done by grasping pin It and moving it in the slot 11 in panel 58. The pin it may However, normally with be set adjacent any of the graduations adjacent slot 11. As the pin 10 is moved toward a higher number adjacent to the slot, the ring member 18 is moved in a counter-clockwise direction as seen on Figure 2. so as to increase the amount of overlap of adjacent gaps. The purpose oi this willbe referred to more particularly hereinafter.

The member It also has three small apertures 01, ll andllwhichare arranged along an are relatively near to the center of member II. and uth 16 which are relatively closely spaced spective openings so as to flt into the openings,- but the broader portion of each of the elements does not have quite the same radial extent as the broader portion of the openings. Each of the elements has a narrow stem-like portion which fits into the guide-ways previously described. The elements I02, I08 and I 04 are slidable radially in their respective openings and the elements may be moved outward radially until their outer edges are flush with the,inner edge of the ring member 13. The elements I02 and I04 are shown in this position in Figure 2. The outer edges of the elements, as is obvious, are arcuate, the are having the same radius as the member 84. From the foregoing it is apparent that when the elements I02, I03 and I04 are moved outward radially, they blank out the gaps in the periphery of member 84, and when these elements are moved inward radially to' the position in which element I03 is shown, the gaps in the periphery of member 84 are again made effective. The portions of member 84 between the gaps act as cam dwells, the same as do the portions of member 13 between its gaps as will presently become apparent. The elements [02, I03 and I04 have the same thickness as member 84 and of course he in the same plane as member 84.

Each of the elements I02, I03 and I04 has a small pin extending perpendicularly to its surface in a direction away from the panel 56. These pins are'designated by the numerals I06, I01 and I08 on Figure 2.

Numeral I 09 designates a disk made of relatively thin spring material having a central opening IIO through which the shaft 55 passes. The disk I09 has three slots in it designated by the numerals III, II: and 3. When the parts are in assembled relationship, the disk I09 is flush with the member 84, with the pins I06, I01 and I08 extending through the slots III, H2 and H8 respectively. The disk I09 has also a pin II5 extending perpendicularly .toits surface through the arcuate slot 95 in'm'ember 84 and through an arcuate slot H6 in the panel 56. The slot I I6. has graduations adjacent it numbered I5, 30 and 80 as shown.

By grasping the pin I I5 and moving it in slot H6, the disk I09 can be rotated, for purposeswhich will presently be described. Each of the slots III, I I2 and H3 has an arcuate portion as shown, the center of the arc in each case being at the center of the disk. Each of .the. slots III and H3 also has a straight portion which slants from the midpoint of the slot toward the center of the disk. The slot II2 has a straight portion which slants from the midpoint of the slot away from the center of the disk.

The disk I 09 has a generally arcuate slot I29, the center of which is spaced from the center of the disk. The portion of the material enclosed by the slot I29 has asmall boss I 2I formed there in, the boss protruding slightly from the surface of the disk on the side adjacent member 84.

The boss I2I cooperates with the three apertures 91, 98 and 99 in member 84, the arrangement being such that the boss may fit into any one 01' the apertures. When the parts are in assembled relationship with the pin H5 opposite the graduation marked 30 of slot N8. the

as may be seen in Figure 1,

disk I09 is in a position with boss I2I engaged in aperture 98 and with the pins I08, I01 and I08 at the midpoints of their respective slots in disk I09. Under these circumstances the elements I02, I03 and I04 are in the position shown in Figure 2 Thus member 84 has only two effective gaps, as will appear later. The timing mechanism with thel arts in this position will produce two timed operations of the stoker per hour.

If the pin IIS should now be moved to the right end of slot IIS opposite the graduation marked I5, the disk I09 will be rotated in a counter-clockwise direction, .as seen on Figure 2, the boss I2I being moved out of aperture 98 and to the left 'into aperture 91. The material enclosed within the slot I29 of disk I 09 is flexed outwardly, that is, away from member 84, when the disk I09 is rotated, the boss I2I acting as a cam bearing against the material at the periphery oi." the aperture which the boss is in at the beginning of the rotation of the disk I09. Thus when the disk I09 is rotated, the material enclosed by slot I29 is flexed slightly out of the plane of thedisk. The boss I2I acts as a detent to hold the disk I09 securely in any one of its three positions.

When the pin 5 is thus moved to the right end of slot II 6, thereby rotating the disk I09.

in a counter-clockwise direction as seen on Figlire 2, the pins ms and ma move to the ends or the straight portions of their respective slots. The pin I 01 moves to the end of the arcuate portion of its respective slot. During the operation as just described, it will be understood that the disk moves and that the pins extending through the slots III and H3 also move. The

straight portions of the slots III and H3 act in the manner of a cam to force their respective pins radially toward the center of member 84, thereby movingthe elements I02 and I04 into positions corresponding to .the position in which element I03 is shown in Figure 2., Rotation of disk I09 in a counter-clockwise direction does not cause pin I01 to move because the slot II2 of disk I09 is merely moved from a position at which the pin I01 is at the midpoint of .the slot II: to a position wherein the pin I01 is at the end of the arcuate portion of the slot I I2. Obviously, counter-clockwise movement of disk I09, as Just described, does not require movement of pin I01 and consequently element I03 remains in the position shown in Figure 2. Thus, with the pin IIS at the right end of slot II6, all of the gaps in the periphery of member I 04 are made efiective and under these circumstances, as will presently appear, the timing mechanism causes the stoker to operate every fifteen min utes. The numerals adjacent the slot H6 designate minutes of time. When the pin I I5 is at the midpoint of slot II6, as shown in Figure 3,

the parts are in the positions shown in Figure 2,

slot IIS adjacent the graduation marked 60,

the disk I 09 is rotated in a clockwise direction as seen on Figure the boss I2I moving from aperture 98 to aperture 99 so as to hold the disk in its third position. When the disk I 09 is so rotated, the arcuate portions of slots III and H8 move relatively to pins I08 and I08, this movemeat of the disk I" not requiring movement of the pins I" and I so that the elements I22 and I remain in the positions in which they are shown in Figure 2. However, when disk I" is thus rotated clockwise, pinifl moves in the straight portion of its respectiveslot to the end of the slot, the slot acting in the manner of a cam to force the pin Ill radially away from the center of member N. This moves element is: to a position corresponding to the positions in which elements I22 and I are shown in Figure 2. Thus, when the pin III is at the left end of slot Ill, only gap 24 of member 24 is eilective,

and under these circumstances, as will presently appear, the time mechanism produces an operat'on of the stoker once every sixty minutes.

The ratchet wheel 52 has member I attached thereto, the bracket member I22 being formed from a relative narrow strip of material shaped substantially into the form of a square. Two of the corners of the square are secured to the ratchet wheel I3 by rivets or the like, as may be seen best in Figure 1. =Another corner of bracket member I2! is bent outwardly somewhat from the ratchet wheel 52, and this corner has a projecting nnger comprising an angular portion I2I and a portion I22 parallel to the plane of the ratchet wheel. The portions I2I and I22 form a cam follower disposed at a radial distance from the center of the ratchet-wheel so as to bear against adjacent portions of cam members 12 and I as the ratchet wheel is rotated. The cam follower is visible on Figure 2 through a rectilinear opening I22 in the ratchet wheel 2. Bracket member I2. is normally urged against the cam members is and II, by the upward force exerted by bracket 02. The cam follower member I22, as pointed out above, bears against both cam members 12 .and 24, and its width or radial extent is such that whenever the cam follower is at a point in its rotation where adjacent gaps in the cam members 12 and I4 overlap, the cam member will drop in against the panel I. (it being remembered that the cam members 12 and 24 are flush with the" panel member), that is, the bracket member 22 will move the ratchet wheel upwardly, as seen in Figure 1, with a relatively quick or snap movement whenever. the cam follower I22 is at a point where adjacent gaps in the cam members I2 and I4 overlap. This movement of the ratchet wheel and bracket member s: will move normally closed contacts ll and it out of enga ement and will move contacts as and u into engagement with a relatively quick or snap action. 1

As seen on Figure 2, member 12 is normally adjusted so that its gaps extend beyond the gaps in member N a certain amount in a clockwise direction. Thus after the cam follower I22 has dropped into adjacent gaps where they overlap, the cam follower will be lifted again, that is moved downwardly looking at Figure i, when it reaches the clockwise extremity of the gap in member I. For instance, if thecam follower I22 dropped into the adjacent gape 22 and N, the

' cam follower will be moved back to its normal position when it engages the shoulder forming the clockwise extremity of gap 04. The cam follower will not be raised suddenly out of tls gape. but its angular portion I2I will en e theshoulder at the extremity of the gap in member N andthisangularportionwillcausethecamfollcwertobemoreorlessgraduallycammedout o! the gaps thereby moving the ratchet wheel I! outwardly, that is downwardly looking at l'lgul'e 1, relatively slowly. Consequently. as ratchet wheel I! is thus moved, the bracket 82 will be moved downwardly, looking at Figure 1, relatively slowly so as to disengage contacts 24 and it and to bring contacts ll and Cl into engagement, the latter contacts being engaged a brief period of time after contacts N and I2 disencage. The purpose of this manner of operation of the contacts will presently become apparent.

Referring now to the operation of my system as a whole, the relay 2. may be energized by the thermostat II whenever there is a demand for heating in the space where the thermostat is located. When the temperature in the space drops to 70, blades I2 and I4 engage their respective contacts completing a circuit for relay 20 as follows: from secondary 22 of transformer 21 through wire I", contact II, blade I2, element I2, blade I4, contact I, wire Ill, wire I22, winding 2| and wire I" back to secondary 2!. Energization of winding 2I moves blades 22 and 22 of the relay into engagement with their respective contacts. Engagement of contact 2| and blade 22 completes a maintaining circuit for the relay which is independent of contact II. this circuit being as follows: from secondary 2! of the transformer through wire I, contact II, blade It, element I2, wire IlLblade 22, contact 2!, wire I", bracket 22, contacts I and 22, bracket 22, wire I22, winding 2I and wire I22 back to secondary 2|. Inasmuch as this circuit is independent of contact Il, it is apparent that after the relay has been energised, it will not be deenergized until the space temperature rises to 72, at which temperature, blade I2 disengages contact II. Whenever the relay is energized bringing contacts 22 and 26 into engagement, the stoker is operated through the following circuiti from line conductor 20 through wire ll, fuse 2!, manual switch 22, wire 21, wire I", blade 22, contact 24, wire I", the stoker and wire I" to line conductor 2|.

When the weather is relatively mild, and there are infrequent demands for stoker operation the relay'as follows: from secondary 29 through wire Ill, wire I40, bracket ll, contacts as and N, bracket 22, wire I22, winding 2| and wire I" back to secondary 2|. Completion of this circuit energizes the rela and the stoker is operated in the same manner as described above. The stoker continues operating until the cam follower is raised by the shoulder at the clockwise extremity of the gap in member 84 as described above. When this occurs, contacts 24 and I are brought into enga ement for a brief lay and contacts II and I are again brought into engagement. As explained above, contacts I and I are brought into engagement for a brief period of time after contacts N and It are disengaged. The purpose of this is as follows. it may happen that during the time the relay is energized by the timing mechanism, blade II of the thermostat may be brought into engagement with contact II.- This position of the thermostat is not one demanding stoker operation, but it is .one wherein the'thermostatic maintaining circuit stances it may to be deenergized so as to disengage blade 23' from contact 25. Therefore, the operation is such that when contacts 64 and 66 disengage,

relay 20 becomes deenergized before contacts 65 F and 68 are engaged.

As previously pointed out, the ratchet wheel 53 is rotated at a speed of one revolution per hour. The number of minutes that the stoker is operated during a timed operation is of course dependent upon the length of time that the cam follower I22 is in one or the depressions .formed by overlapping adjacent gaps in the members 13 and 84. When the pin 16 is moved to the left end of slot 11 (Figure 3) adjacent the graduation marked I, (this would mean movement of pin the gaps in the periphery of cam 84 are made eflective as described above, and inasmuch as there ar four gaps, there will now be four timed operations of the stoker per revolution of ratchet I wheel 53, that is per hour, or in other words, there will be a, timed operation of the stoker every fif-- teen minutes.

From the foregoing it will be apparent to those skilled in the art that I have provided a timing arrangement having manifold advantages, it being of a very simple but effective nature. The arrangement provides simple means of adjusting the length and number of operating periods utilizing very small and inexpensive parts. Most 16 to the right in Figur 2) adjacent gaps-in the members I3 and 84 are brought into registry with each other. such that under these circumstances the timed The angular extent of the gaps is operations of the stoker are of seven minutes duration as indicated by the numeral adjacent the slot 11'. As th pin 16 is moved to the right end in slot 11, as seen on Figure 3, the amount of overlap of adjacent gaps is reduced, and con- 1 sequently the length of timed'operations of the stoker is correspondingly reduced to a number of minutes determined by the number adjacent slot 11 at which the pin 16 is positioned.

Under different operating condition and with different types of fuel, itis sometimes desirable to provide for different ing operation. That is, under some circumbe desirable to operate the stoker once' an hour minutes, or it stoker twice or may :be desirable to operate the four times an hour for the same number of minutes or for a diilerent number of Programs of fire maintain? v for a predetermined number of operations during one cycle lasting a given period of time, I have providedthe adjustment comprising the pin 5 in slot 6. As described above, this adjustment varies the number of effective gaps in the cam member 84. Whenever a gap in the cam member 84 is blanked out to render it ineffective in the manner already described, the corresponding adjacent 88D in th member 13 is of course also rendered ineffective. When the pin H5 is at the midpoint of slot I ll, two of the gaps in member 84 are effective and two are ineflective as already described. Under these circumstances, there will be two timed operations of the stoker every hour, it :being remembered that the ratchet wheel 53 makes one revolution per hour, or in other words, there will be a timed operation of the stoker every thirty minutes. If it is desired that there be only one timed operation per hour, the pin Hlis moved to the left end of slot H6. Under these circumstances, all of the gaps of above, are made and consequently ineffective except the gap 94 there is only one timed operation of the stoker per hour or per revolution of the ratchet wheel 53. If it is desired that there be a timed operation of the stoker every fifteen minutes, the' pin 5 is moved to the right end of slot 6. Under these circumstances all of of the elements comprising the timing mechanism are fiat and are disposed in parallel planes lying very close to each other or in the same plane, so that the timing unit as a whole has an extremely small depth, and its largest dimensions need be but little greater than the diameter of the ratchet wheel. Obviously, the nature of the construction and arrangement of parts is such that the entire unit can be made to occupy a minimum of space even though the construction is such that the'action is positive and the use of delicate parts or theuse of parts subject to rapid deterioration is avoided.

The embodiment of my invention which I have disclosed is representative of its preferred form although there'are modifications and variations which may be made by those skilled in the art. My invention is not to be limited by my disclosure which is illustrative, but its spirit and scope is appended claims. 7

I claim as my invention:

1. In a timing device, in combination, mea comprising a relatively flat circular cam member having circularly arranged, spaced dwells and depressions betweenthe dwells, means forming a fiat ring-shaped member surrounding said first member with the fiat'faces of said ringshaped member and said first member in substantially the same plane, said ring-shaped member having portions forming alternate dwells and depressions along its inner edge, the latter dwells and depressions being adjacent corresponding. dwells and depressions in the first member, said mem here being relatively adjustable to vary the amount of overlap of said corresponding dwells and depressions, a cam follower member adapted toride on both said members so as to drop into cam member 84, as described ing portions forming alternate dwells and dethe depressions in the members where the adjacent depressions overlap, the eifective length of the dwells and depressions as respects actuation of the cam follower member depending upon the relative adjustment-of the cam members, ad-

'Justable means associated with one of said members comprising an element adapted to bridge adjacent dwells of said one member whereby to blank out the depressions therebetween, and

means for moving said element radially as respects the circularly arranged dwells and depressions into the path of said cam follower whereby the number of effective cam dwells is varied.

2. In a' timing device, in combinationfrneans comprising a relatively flat circular cam mem-.

her having circularly arranged, spaced dwells and depressions between the dwells, means forming a fiat ring-shaped member surrounding said first member with the flat faces of said ring shaped member in substantially pressions along its inner edge, thelatter dwells and depressions being adjacent corresponding dwells and depressions in the first member, said members being relatively adjustable to vary the amount oi overlap oi said corresponding dwells and depressions, and a cam iollower member adapted to ride on both said members so as to drop into the depressions in the members where the adjacent depressions overlap, the efiective length of the dwells and depressions as respects actuation of the cam follower member depending upon the relative adjustment of the cam members, adjustable means associated with one oi said members comprising an element adapted to bridge adjacent dwells of said one member whereby to blank out the depressions therebetween, and means ior moving said element radially as respects the circularly arranged dwells and depressions into the path oi said cam iollower whereby the number oi efiective cam dwells is varied, said last means comprising a rotatable disk having a slot therein, said element having a pin engaged in said slot, the slot being so shaped and positioned that as the disk is rotated, the pin is constrained to move in the slot in a manner to move the element radially.

3. In a timing device, in combination, means comprising a relatively fiat circular cam member having circularly arranged, spaced dwells and depressions between the dwells, means forming a fiat ring-shaped member surrounding said first member with the fiat faces oi said ring shaped member and said first member in the same plane, said ring-shaped member having portions forming alternate dwells and depressions along its inner edge, the latter dwells and depressions being adjacent corresponding dwells and d'epressions in the first member, said members being relatively adjustable to vary the amount oi overlap of said corresponding dwells and depressions, and a cam follower member adapted to ride on both said members so as to drop into the depressions in the members where the adjacent depressions overlap, the efiective length of the dwells and depressions as respects actuation oi the cam follower member depending upon the relative adjustment oi the cam members, adjustable means associated with said first member comprising an element adapted to bridge adjacent dwells of said first member whereby to blank out the depressions therebetween, means ior moving said element radially as respects the circularly arranged dwells and depressions into the path oi said cam iollcwer whereby the number oi eifectivecam dwells is varied. said last means comprising a manually adjustable plate having a slot therein, said element having a pin engaged in said slot, the slot being so shaped and positioned that as the plate is moved the pin is constrained to move in the slot in a manner to move the element radially.

4. In combination; a cam disk assembly and a cam icllcwer disk; means for mounting said cam follower disk and said cam disk assembly in parallel planes for relative rotation about a common axis; and means for causing relative rotation at said cam follower disk and said disk assembly about said eommonaxis; said cam disk assembly comprising a substantially fiat circular cam disk having alternately arranged dwells and depressions along its periphery, and a'substantiailyfiatsecondcammember havingaeircular openin to the external diameter oi said circular cam disk, said second cam member beirl mounted surrounding said circular cam disk withtbe iaces substantially corresponding in dhmeter oi said cam members in a common plane, said second cam member having alternately arranged dwells and depressions along the edge of said circular opening, said circular cam member and said second member being rotatably adjustable with respect to each other to vary the amount of overlap of the dwells and depressions of the respective members; and said cam follower disk having a cam follower portion projecting axially into engagement with said cam disk assembly, said cam follower portion engaging both the outer portion of said circular cam member and the inner portion of said second cam member so as to drop into the depressions in said cam members only where said depressions overlap.

5. In combination; a cam disk assembly and a cam follower disk; means for mounting said cam follower disk and said cam disk assembly in parallel planes ior relative rotation about a common axis; and means for causing relative rota- ,tion of said cam iollower disk and said disk assembly about said common axis; said cam disk assembly comprising a substantially flat circular cam disk having alternately arranged dwells and depressions along its periphery, and a substantially fiat second cam member having a circular opening substantially corresponding in diameter to the external diameter of said circular cam disk, said second cam member being mounted surrounding said circular cam disk with the iaces of said cam members in a common plane, said second cam member having alternately arranged dwells and depressions along the edge of said circular opening, said circular cam member and said second member being rotatably adjustable with respect to each other to vary the amount oi overlap of the dwells and depressions oi the respective members, said circular cam disk having blanking members associated with certain oi said depressions and adapted to be moved to a position in which they blank out said depressions;

and said cam follower disk having a cam followerportion projecting axially into engagement with said cam disk assembly, said cam follower portion engaging both the outer portion of said circular cam member and the inner .portion oi said second cam member so as to drop into the depressions in said cam members only where said depressions overlap.

6. In combination; a cam disk assembly and a cam iollower disk; means for mounting said cam follower disk and said cam disk assembly in parallel planes for relative rotation about a common axis: and means for causing relative rotation of said cam follower disk and said disk assembly about said common axis; said cam disk assembly comprising a substantially fiat circular cam disk having alternately arranged dwells and depressions along its periphery, and a substantiallv fiat second cam member having a circular opening substantially corresponding in diameter to the external diameter at said circular cam disk, said second cam member being mounted surrounding said circular cam disk with the iaces of said cam members in a common plane, said second cam member having alternately arranged dwells and depressions along the edge of said circular opening, said circular cam member and said second member being rotatably adjustable with respect to each other to vary the amount of overlap of the dwells and depressions--.c .the respective members, said circular cam disk having blanking members associated with certain of 7s laiddepreesionsandadaptedtobemovedtoa lar cam disk having blanking members associposition in which they blank out said depressions;

and means comprising a further disk rotatable about said axis for selectively moving one or more of said blanking members into blankingv position; and said cam follower disk having a cam follower portion projecting axially into engagement with said cam disk assembly, said cam follower portion engaging both the outer portion of said circular cam member and the inner portion of said second cam member so as to drop into the depressions in said cam members only where said depressions overlap.

7. Incombination; a cam disk assembly and a cam follower disk; a control panel; means for mounting said cam follower disk and said cam disk assembly parallel to said panel for relative rotation of said cam follower disk and cam disk assembly about a common axis; and means for causing relative rotation of said cam follower disk and said disk assembly about said common axis; said cam disk assembly comprising a substantially flat circular cam disk having alternately arranged dwells and depressions along its periphery, a substantially flat second cam member hav ing a circular opening substantially corresponding in diameter to the external diameter of said circular cam disk, said second cam member being mounted surrounding said circular cam disk with the faces of said cam members in a common plane. said second cam member having alternately ar-' ranged dwells and depressions along the edge of said circular opening, said circular cam member and said second member being rotatably adjustable with respect to each other to vary the amount of overlap of the dwells and depressions of the respective members, and a knob secured to one of said cam members and projecting through anarcuate slot in said control panel for rotatably adjustingsaid members with respect to each other; and said cam followerdisk having a cam follower portion projecting axially into engagement with said cam disk assembly, sa d cam follower portion engaging both theouter portion of said circular cam member and the inner portion of said second cam. member so as to drop into the depressions in said cam members only where said v depressions overlap.

8. In combination; a cam disk assembly and a cam follower disk; a control panel; means for mounting said cam follower disk and said cam disk assembly'parallel to said panel for relative rotation of said cam follower disk and cam disk assembly about a common axis; and means for causing relative rotation of said cam follower disk and said disk assembly about said common axis; said cam disk assembly comprising acircular cam disk having alternately. arranged dwells and depressions along its periphery. a. second cam member having a circular opening substantially corresponding in diameter to the external diameter of said circular cam disk, said second cam member being mounted surrounding said circular cam disk with the faces of said cam members in a common plane, said second cam member having alternately arranged dwells and depressions along the edge of said circular opening, said circular cam member and said second member being rotatably adjustable with respect to each other to vary the amount of overlap of the dwells and depressions of the respective members; a knob secured to one of said cam members and projecting through an arcuate-slot in said control panel for rotatably adjusting said members with respect to each other; said circuated with certain of said depressions and adapted to be moved to a position in which they blank out said depressions; and means comprising a further knob ,operatively connected to said blanking members and projecting through a further arcuate slot in said control panel for selectively moving one ormore of said blanking members into blanking position; and said cam follower disk having a cam follower portion projecting axiallyinto engagement with said cam'disk-assembly, said cam follower portion engaging both the outer portion of said circulancam member and the inner portion of said second cam member so as to drop into the depressions in said cam members only where said depressions overlap.

9. In combination; a cam disk assembly and a cam-follower disk; 8. control panel; means for I mounting said cam follower disk and said cam disk assembly parallel to said panel for relative rotation of said cam follower disk and cam disk assembly about a common axis; and means for causing relative rotation'of said cam follower disk and said disk assembly about said common member being mounted surrounding said circular I cam disk with the faces of said cam members in a common plane, said second cam member having alternately arranged dwells and depressions on its face along the edge of said circular opening, said circular cam member and said second member being rotatablyadjustable with respect to each other to vary the amountoi' overlap of the dwells and depressions of the respective memhere, said circular cam disk having blanking members associated with certain of said depressions and adapted to be moved to a position in which theyxblank out said depressions; means, comprising a further disk rotatable about said axis for selectively moving one or more of said blanking members into blanking position; and a knob secured to' said disk and projecting through-an arcuate slot in s'aidpanel for rotating said disk and hence varying the position of said blanking members; and said cam follower disk having a cam follower portion projecting axially into engagement with said cam disk assembly, said cam follower portion engaging both the outer portion of said circular cam member and the inner portion of said second cam memmembers only where said depressions overlap.

10. In combination; a cam disk and a cam follower; means for causing relative rotation of said cam follower and cam disk; said cam disk having alternately arranged annular dwells and de- 'pressions forming a circular cam track on the face of said disk with the center of said circular track on said axis, said cam disk having slots connecting with'certain-of said depressions, said slots extending radially inwardly with respect to the center of said circular track, and blanking members disposed in said slots with their outer faces hub with the outer face of the cam disk, said blanking members being radially slidable in said slots into and out of said depressions so as to either fill said depressions flush with the face of said cam or to leave said depressions open; a further disk disposed adjacent said cam disk and revolvable about said axis; and means operatively connecting said further disk and said blanking members and effective upon said further disk being rotated to shift various ones of said blanking members into said depressions.

11. In combination; a cam disk and a cam follower disk; means for mounting said cam disk and cam follower disk in parallel planm for relativerotation about a common axis; said disks being axially movable with respect to each other and being biased towards each other; means for causing relative rotation of said cam follower disk and cam disk about said common axis; said cam disk having alternately arranged annular dwells and depressions forming a circular cam track on the face of said disk with the center of said circular track on said axis, said cam disk having slots connecting with certain of said depressions, said slots extending radially inwardly with respect to the center of said circular track, and blanking members disposed in said slots with their outer faces flush with the outer face of the cam disk, said blanking members being radially slidable in said slots into and out of said depressions so as to either fill said depressions flush with the face of said cam or to leave said depressions open; a further disk disposed adjacent said cam disk and revolvable about said axis; and means operatively connecting said further disk and said blanking members and effective upon said further disk being rotated to shift various ones of said blanking members into said depressions; and said cam follower having a cam follower portion projecting axially into engagement with said cam diskscasto causesaiddisks toperiodicallymove apart axially against their bias.

12. In a time switch; a cam disk and a cam follower disk; means for mounting said cam disk and cam follower disk about a shaft for relative rotation; said disks being axially movable with respect to each other and being biased towards each other, said cam disk having alternately arranged annular dwells and depressions forming a circular cam track; means for varyingthe effective length of said dwells, said cam follower disk having a cam follower portion projecting axially into engagement with said cam track; a switch; a switch actuating member movable ax ially of said shaft to change the circuit controlling position of said switch; means operatively connecting said switch actuating member to one of said disks; and means for rotating one of said disks with respect to the other so that said disks are periodically moved apart axially against their bias to move said switch actuating member.

13. In a time switch; a cam disk and a cam follower disk; means for mounting said cam disk and cam follower disk about a shaft for relative rotation; said disks being axially movable with respect to each other and being biased towards each other; said cam disk having alternately arranged annular dwells and depressions forming a circular cam track; means for varying the effectivelength and number of said dwells; said cam follower disk having a cam follower portion projecting axially into engagement with said cam track; a switch: a switch actuating member movable axially of said shaft to change the circuit controlling position of said switch; means operatively connecting said switch actuating member to one of said disks; and means for rotating one of said disks with respect to the other so that said disks are periodically moved apart axially against their bias to move said switch actuatin member.

14. In a time switch; a control panel; a cam disk and a cam follower disk; means for-moimting said cam disk and cam follower disk parallel to said control panel about a shaft for relative rotation with respect to each other; said disks being axially movable with respect to each other and being biased towards each other; said cam disk having alternately arranged annular dwells and depressions forming a circular cam track; means accessible from said control panel for varying the effective length and number of said dwells; said cam follower disk having a cam follower portion projecting axially into engagement with said cam track; a switch; a switch actuating member movable axially of said shaft to change the circuit controlling position of said switch; means operatively connecting said switch actuating member to one of said disks; and means for rotating one of said disks with respect to the other so that said disks are periodically moved apart axially against their bias to move said switch actuating member.

15. In a timer, a power operated rotatable element, said element also being axially movable, means to effect successive axial movements of said member comprising a pair of disks, said element having a part normally abutting said disks but being freed therefrom by rotation of said element, and a movable controlling member, the movement of which is controlled by the axial movements of said element.

16. In a timer, a power operated rotatable element, said element also being axially movable, means to effect successive axial movements of said member comprising a pair of disks, said element having a part normally abutting said disks but being freed therefrom by rotation of said element, and a controlling member the movement of which is controlled by the axial movements of said element, said part comprising a spring pressed member projecting toward the disks and the latter each having a slot therein to receive said member when registering therewith.

17. In a timer, a power operated rotatable element, said element also being axially movable, means to effect successive axial movements of said element comprising a pair of disks, said element having a part normally abutting said disks but being freed therefrom by rotation of said element, and a movable controlling member the movement of which is controlled by the axial movements of said element, said part comprising a spring pressed member projecting toward the disks, and the latter each having a slot therein to receive said member when registering therewith and said element being free for continued rotation relatively to said disks in any position of the latter.

18. In a timer, a power operated rotatable element, said element also being axially movable, means to effect successive axial movements of said member comprising a pair of disks, said element having a spring pressed part normally abut-- ting said disks but before being freed therefrom by rotation of said element and a movable con trolling member, the movement of which is controlled by axial movemcnt of said element.

19. In a timer, a power operated rotatable element, said element also being axially movable, means to effect successive axial movements of said member comprising a pair of disks, said element having a part adapted to be engaged and released successively by said disks to permit axial movement of said element and a movable controlling member, the movement of which is controlled by axial movement of said element.

ALBERT E.BA AK.

cmmrxc'im or CORRECTION; Patent No. aga nst. December 191m.

- AIBER'I E. mum.

It is hereby certified that error appears fin the printed sbecification of the above numbered patent requiring correction as follows: Page A, sec- 0nd column, line 614-65, strike out "68 are brought into engagement for a brief lay" and insert instead --66 are disengaged for deenergizing the relay-- and that the said Letters Patent should be read with this cqrrection therein that the same may conformto the recerd of the case inthe Patent Office. A

Signed and sealed tnis 5th day of J1me, A. D. 1919.5

Leslie Frazer (Seal) Acting Commissioner of Patents. 

